Studies with nonradioisotopic sodium chromate

A recently developed nonradioisotopic 52Cr technique was used to measure either red cell volume or posttransfusion recovery of stored red cells. The experimental method uses Zeeman electrothermal atomic absorption spectrophotometry to measure red cell chromium. Results from the 52Cr method were compared with those from 51Cr single‐label and 125I‐albumin/51Cr double‐label procedures using 49‐day AS‐1 red cell concentrates drawn and prepared according to standard procedures. In the first group of five donors, red cell volume was estimated concurrently with both 52Cr‐labeled fresh red cells and 125I‐albumin. The latter measured plasma volume from which red cell volume was estimated on the basis of the hematocrit (125I red cell volume). 51Cr‐labeled stored red cells were transfused to measure posttransfusion recoveries. The correlation between 52Cr and 125I red cell volumes was significant (r = 0.68, p < 0.01), and, in this group, the differences were not significant (p > 0.05). Twenty‐four‐hour posttransfusion recoveries of 51Cr‐labeled stored red cells averaged 66 ± 5 percent when measured with the 125I/51Cr technique and 69 ± 8 percent when measured with the 52Cr/51Cr method. In the second group of five donors, red cell volume was estimated by the 125I‐albumin technique, and the posttransfusion recovery of stored red cells was quantitated by 51Cr‐ and 52Cr‐labeled stored cells simultaneously. In this group, posttransfusion recoveries with 125I/51Cr averaged 73 ± 7 percent; with 125I/52Cr, they averaged 75 ± 10 percent. Using the single‐label method of calculation, recoveries averaged 76 ± 7 and 75 ± 10 percent for the 51Cr and 52Cr methods, respectively. Calculated mean posttransfusion recoveries for the total group (n = 10) showed a small but significantly lower (p < 0.05) posttransfusion recovery with the double‐label 125I/51Cr technique (69 ± 7%) than that with the single‐label 51Cr method (74 ± 7%). The nonradioisotopic 52Cr technique provided an acceptable measure of posttransfusion recovery when used in a double‐label method, either for the determination of red cell volume concurrent with 51Cr‐labeled stored cells or for the labeling of stored cells with an independent measure of red cell volume.